Coordinated Packet Data Network Change for Selected Internet Protocol Traffic Offload

ABSTRACT

Coordinated P-GW change for SIPTO may be provided. A WTRU may send and/or receive one or more flows via a first PDN connection and via a first P-GW. The WTRU may send an indication to the network that at least one flow of the first PDN connection is available for SIPTO. The indication may include one or more SIPTO preferences. The WTRU may receive a message from a MME. The message may trigger establishment of a second PDN connection via a second P-GW. The WTRU may move, while maintaining the first PDN connection, the at least one flow from the first PDN connection to the second PDN connection. The WTRU may deactivate the first PDN connection when the one or more flows have been moved to the second PDN connection and/or when no information has been received via the first PDN connection after a predetermined duration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the Continuation of U.S. patent application Ser. No.15/892,964, filed Feb. 9, 2018, which is a Continuation of U.S. patentapplication Ser. No. 15/033,313, filed Apr. 29, 2016, which issued asU.S. Pat. No. 9,930,597 on Mar. 27, 2018, which was the National Stageentry under 35 U.S.C. § 371 of Patent Cooperation Treaty ApplicationPCT/US2014/063259, filed Oct. 30, 2014, which claims the benefit of U.S.Provisional Patent Application No. 61/897,771, filed Oct. 30, 2013, thecontents of which are hereby incorporated by reference herein.

BACKGROUND

Networks that utilize small cells (e.g., Home eNodeB devices) aregaining momentum in the marketplace. Examples of small cells may includecells that are served by relatively lower power base stations, forexample including relatively lower power evolved Node B (eNB) devicessuch as home eNBs (HeNBs), Relay Nodes (RNs), Remote Radio Heads (RRHs),and/or the like. The small cell base stations may have a relativelysmaller coverage area as compared to a macro cell. Such small cells areoften added to a network to increase capacity in areas with high levelsof user and/or to provide additional coverage in areas not covered bythe macro network—e.g., both outdoors and/or indoors. Small cells canalso improve network performance and service quality by facilitating theoffloading of traffic from the large macro-cells. Such heterogeneousnetworks with large macro-cells in combination with small cells canprovide increased bitrates per unit area.

An offloading technique known as Selected IP Traffic Offload (SIPTO) mayallow an operator to select a packet data network (PDN) gateway (PDN GWor P-GW) for one or more wireless transmit receive units (WTRUSs) thatmay take into account the location of the WTRU. The WTRU's PDNconnection may be torn down and reestablished if the network realizes itmay be advantageous to do so, for example, based on the location of theWTRU. Such techniques for reselecting a PDN GW that is closer to theactual location of the WTRU may facilitate more efficient routing ofdata within the core network, thereby more efficiently utilizing networkresources. SIPTO may be used to enable local breakout of traffic from asmall cell.

SIPTO may allow an operator to streamline an established PDN connectionby reassigning a new P-GW that may be geographically closer to thecurrent location of a WTRU. P-GW relocation may imply a change in IPaddress, and performing SIPTO may disrupt any ongoing services. It hasbeen recommended that SIPTO should not be performed for WTRUs in aconnected mode to avoid disrupting ongoing services. While thisrecommendation may represent an improvement compared to blindlyperformed SIPTO, it fails to address the issue of smooth P-GW relocationfor WTRUs with long-lived and real-time IP flows, e.g. long conferencecalls, large file transfers, and the like.

SUMMARY

SIPTO may be performed to avoid service disruptions due to an IP addresschange. A WTRU may send and/or receive one or more flows via a first PDNconnection. The WTRU may send an indication to the network that at leastone flow of the first PDN connection is available for SIPTO. Theindication may indicate one or more other flows of the first PDNconnection for which SIPTO is not allowed. The first PDN connection maybe via a first P-GW. The indication may include one or more SIPTOpreferences. The indication may include a SIPTO allowed tag. Theindication may be sent via a non-access stratum (NAS) message to a MMEin the network. The indication may be sent at a bearer level, an IP flowlevel, and/or an application level. When the indication is sent at theapplication level, the indication may include an application IDindicating a SIPTO allowed status that corresponds to an applicationbeing executed at the WTRU. When the indication is sent at the bearerlevel, the indication may indicate one or more bearers available forSIPTO. The indication may be sent, for example, when an applicationbeing executed at the WTRU is closed or stopped. As another example, theindication may be sent when a display of a WTRU enters an idle state.

The WTRU may receive a message from the MME. The message may triggerestablishment of a second PDN connection via a second P-GW. The WTRU mayestablish the second PDN connection via the second P-GW. The WTRU maymove, while maintaining the first PDN connection, the at least one flowfor which it was indicated that SIPTO was allowed from the first PDNconnection to the second PDN connection. The WTRU may deactivate thefirst PDN connection. For example, the WTRU may deactivate the first PDNconnection when the one or more flows have been moved to the second PDNconnection. As another example, the WTRU may deactivate the first PDNconnection when no information has been received via the first PDNconnection after a predetermined duration.

A MME in the network may receive, from a WTRU, an indication that atleast one flow of a first PDN connection is available for SIPTO and/orthat one or more other flows may not be moved using SIPTO. Theindication may include one or more SIPTO preferences and may be receivedat a bearer level, an IP flow level, or an application level. When theindication is received at the bearer level, the indication may indicateone or more bearers available for SIPTO. When the indication is receivedat the application level, the indication may include an application IDindicating a SIPTO allowed status that corresponds to a runningapplication on the WTRU.

The MME may receive a list of applications from the WTRU. The MME maydetermine one or more bearers to offload based on the list ofapplications. The MME may determine whether to perform SIPTO for one ormore flows of the first PDN connection. The MME may send a message, tothe WTRU, that triggers establishment of a second PDN connection via asecond P-GW. The message may include a NAS message. The message mayconfirm an accuracy of the list of applications. The message may be afirst NAS message. The indication may be a second NAS message. Thesecond NAS message may include a SIPTO allowed tag. The MME may performa serving gateway (S-GW) relocation. The MME may receive, from aneNodeB, a local HeNB (LHN) identification (LHN-ID) of the second PDNconnection. The MME may send the LHN-ID of the second PDN connection tothe WTRU. The LHN-ID may include an IP address of a P-GW associated withthe second PDN connection.

The MME may separate an access point name (APN) aggregate maximumbit-rate (APN-AMBR) into a first APN-AMBR associated with the first PDNconnection and a second APN-AMBR associated with the second PDNconnection. The MME may receive subscription data. The subscription datamay include the APN-AMBR. The MME may determine a modified firstAPN-AMBR. The MME may signal the modified first APN-AMBR to an eNodeB.The MME may send a modified bearer command to a S-GW. The modifiedbearer command may identify the modified first APN-AMBR. The S-GW mayenforce the first and second APN-AMBR.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented.

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A.

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

FIG. 1D is a system diagram of another example radio access network andanother example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1E is a system diagram of another example radio access network andanother example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 2 illustrates an example call flow for a SIP session withre-invite.

FIGS. 3 and 4 illustrate an example network employing amake-before-break SIPTO PDN connection.

FIGS. 5 and 6 illustrate an example network employing make-before-breakSIPTO for the case of SIPTO@LN with standalone LGW.

FIGS. 7 and 8 illustrate an example network employing make-before-breakSIPTO for the case of SIPTO@LN with collocated LGW.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments will now be describedwith reference to the various Figures. Although this descriptionprovides a detailed example of possible implementations, it should benoted that the details are intended to be exemplary and in no way limitthe scope of the application.

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications system 100may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, and/or 102 d (whichgenerally or collectively may be referred to as WTRU 102), a radioaccess network (RAN) 103/104/105, a core network 106/107/109, a publicswitched telephone network (PSTN) 108, the Internet 110, and othernetworks 112, though it will be appreciated that the disclosedembodiments contemplate any number of WTRUs, base stations, networks,and/or network elements. Each of the WTRUs 102 a, 102 b, 102 c, 102 dmay be any type of device configured to operate and/or communicate in awireless environment. By way of example, the WTRUs 102 a, 102 b, 102 c,102 d may be configured to transmit and/or receive wireless signals andmay include user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a smartphone, a laptop, a netbook, a personal computer,a wireless sensor, consumer electronics, and the like.

The communications system 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106/107/109, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be a base transceiver station (BTS), a Node-B,an eNode B, a Home Node B, a Home eNode B, a site controller, an accesspoint (AP), a wireless router, and the like. While the base stations 114a, 114 b are each depicted as a single element, it will be appreciatedthat the base stations 114 a, 114 b may include any number ofinterconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 103/104/105, which mayalso include other base stations and/or network elements (not shown),such as a base station controller (BSC), a radio network controller(RNC), relay nodes, etc. The base station 114 a and/or the base station114 b may be configured to transmit and/or receive wireless signalswithin a particular geographic region, which may be referred to as acell (not shown). The cell may further be divided into cell sectors. Forexample, the cell associated with the base station 114 a may be dividedinto three sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, e.g., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 115/116/117,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV), visiblelight, etc.). The air interface 115/116/117 may be established using anysuitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 103/104/105 and the WTRUs 102a, 102 b, 102 c may implement a radio technology such as UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),which may establish the air interface 115/116/117 using wideband CDMA(WCDMA). WCDMA may include communication protocols such as High-SpeedPacket Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may includeHigh-Speed Downlink Packet Access (HSDPA) and/or High-Speed UplinkPacket Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (e.g.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1x, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106/107/109.

The RAN 103/104/105 may be in communication with the core network106/107/109, which may be any type of network configured to providevoice, data, applications, and/or voice over internet protocol (VoIP)services to one or more of the WTRUs 102 a, 102 b, 102 c, 102 d. Forexample, the core network 106/107/109 may provide call control, billingservices, mobile location-based services, pre-paid calling, Internetconnectivity, video distribution, etc., and/or perform high-levelsecurity functions, such as user authentication. Although not shown inFIG. 1A, it will be appreciated that the RAN 103/104/105 and/or the corenetwork 106/107/109 may be in direct or indirect communication withother RANs that employ the same RAT as the RAN 103/104/105 or adifferent RAT. For example, in addition to being connected to the RAN103/104/105, which may be utilizing an E-UTRA radio technology, the corenetwork 106/107/109 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106/107/109 may also serve as a gateway for the WTRUs102 a, 102 b, 102 c, 102 d to access the PSTN 108, the Internet 110,and/or other networks 112. The PSTN 108 may include circuit-switchedtelephone networks that provide plain old telephone service (POTS). TheInternet 110 may include a global system of interconnected computernetworks and devices that use common communication protocols, such asthe transmission control protocol (TCP), user datagram protocol (UDP)and the internet protocol (IP) in the TCP/IP internet protocol suite.The networks 112 may include wired or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another core network connected to one or moreRANs, which may employ the same RAT as the RAN 103/104/105 or adifferent RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment. Also, embodiments contemplate that thebase stations 114 a and 114 b, and/or the nodes that base stations 114 aand 114 b may represent, such as but not limited to transceiver station(BTS), a Node-B, a site controller, an access point (AP), a home node-B,an evolved home node-B (eNodeB), a home evolved node-B (HeNB orHeNodeB), a home evolved node-B gateway, and proxy nodes, among others,may include some or all of the elements depicted in FIG. 1B anddescribed herein.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 115/116/117. For example, in one embodiment,the transmit/receive element 122 may be an antenna configured totransmit and/or receive RF signals. In another embodiment, thetransmit/receive element 122 may be an emitter/detector configured totransmit and/or receive IR, UV, or visible light signals, for example.In yet another embodiment, the transmit/receive element 122 may beconfigured to transmit and receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 115/116/117.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 115/116/117from a base station (e.g., base stations 114 a, 114 b) and/or determineits location based on the timing of the signals being received from twoor more nearby base stations. It will be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination implementation while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 103 and the core network 106according to an embodiment. As noted above, the RAN 103 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 115. The RAN 103 may also be in communicationwith the core network 106. As shown in FIG. 1C, the RAN 103 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 115. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 103. TheRAN 103 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 103 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an lub interface.The RNCs 142 a, 142 b may be in communication with one another via anlur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macrodiversity, security functions, data encryption, and thelike.

The core network 106 shown in FIG. 1C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving GPRS support node(SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each ofthe foregoing elements are depicted as part of the core network 106, itwill be appreciated that any one of these elements may be owned and/oroperated by an entity other than the core network operator.

The RNC 142 a in the RAN 103 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices.

The RNC 142 a in the RAN 103 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between and the WTRUs102 a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1D is a system diagram of the RAN 104 and the core network 107according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 107.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1D, theeNode-Bs 160 a, 160 b, 160 c may communicate with one another over an X2interface.

The core network 107 shown in FIG. 1D may include a mobility managementgateway (MME) 162, a serving gateway 164, and a packet data network(PDN) gateway 166. While each of the foregoing elements are depicted aspart of the core network 107, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 162 may be connected to each of the eNode-Bs 160 a, 160 b, 160 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 164 may be connected to each of the eNode-Bs 160 a,160 b, 160 c in the RAN 104 via the Si interface. The serving gateway164 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 164 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 164 may also be connected to the PDN gateway 166,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 107 may facilitate communications with other networks.For example, the core network 107 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 107 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 107 and the PSTN 108. In addition, the corenetwork 107 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1E is a system diagram of the RAN 105 and the core network 109according to an embodiment. The RAN 105 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 102 a, 102 b, 102 c over the air interface 117. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b, 102 c, the RAN 105, andthe core network 109 may be defined as reference points.

As shown in FIG. 1E, the RAN 105 may include base stations 180 a, 180 b,180 c, and an ASN gateway 182, though it will be appreciated that theRAN 105 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 180 a, 180 b,180 c may each be associated with a particular cell (not shown) in theRAN 105 and may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 117. In oneembodiment, the base stations 180 a, 180 b, 180 c may implement MIMOtechnology. Thus, the base station 180 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a. The base stations 180 a, 180 b, 180 c may alsoprovide mobility management functions, such as handoff triggering,tunnel establishment, radio resource management, traffic classification,quality of service (QoS) policy enforcement, and the like. The ASNgateway 182 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 109, and the like.

The air interface 117 between the WTRUs 102 a, 102 b, 102 c and the RAN105 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 109.The logical interface between the WTRUs 102 a, 102 b, 102 c and the corenetwork 109 may be defined as an R2 reference point, which may be usedfor authentication, authorization, IP host configuration management,and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 1E, the RAN 105 may be connected to the core network109. The communication link between the RAN 105 and the core network 109may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 109 may include a mobile IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements aredepicted as part of the core network 109, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA may be responsible for IP address management, and may enablethe WTRUs 102 a, 102 b, 102 c to roam between different ASNs and/ordifferent core networks. The MIP-HA 184 may provide the WTRUs 102 a, 102b, 102 c with access to packet-switched networks, such as the Internet110, to facilitate communications between the WTRUs 102 a, 102 b, 102 cand IP-enabled devices. The AAA server 186 may be responsible for userauthentication and for supporting user services. The gateway 188 mayfacilitate interworking with other networks. For example, the gateway188 may provide the WTRUs 102 a, 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. In addition, the gateway 188 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

Although not shown in FIG. 1E, it will be appreciated that the RAN 105may be connected to other ASNs and the core network 109 may be connectedto other core networks. The communication link between the RAN 105 theother ASNs may be defined as an R4 reference point, which may includeprotocols for coordinating the mobility of the WTRUs 102 a, 102 b, 102 cbetween the RAN 105 and the other ASNs. The communication link betweenthe core network 109 and the other core networks may be defined as an R5reference, which may include protocols for facilitating interworkingbetween home core networks and visited core networks.

With SIPTO at a Local Network (SIPTO@LN), a P-GW (e.g., alias LocalGateway) may be relocated (e.g., moved even further) toward a networkedge and may be collocated with an eNodeB. SIPTO@LN may lead to arelatively flat architecture (e.g., IP traffic can be broken out closeto the network edge). With SIPTO@LN, frequency of service disruption dueto SIPTO may increase (e.g., due to smaller coverage of the LocalGateway).

Service disruption due to an IP address change may include one or moreeffects on short-lived and/or long-lived/real-time flows. For example,for short-lived flows (e.g., web browsing) the service disruption due toa SIPTO-induced IP address change may be relatively mild. In some case,a user executing a relatively short-lived flow may not notice anythingwhen SIPTO is performed within the network. In some examples, althoughthe short-lived flow user may notice a slight disruption, the servicedisruption may be slight. For example, the user may interact (e.g.,briefly interact) with a user interface, for example, by selecting a webpage link after a “network connection lost” error, selecting a refreshicon, and/or the like. However, for long-lived and real-time flows, theeffect of service disruption due to SIPTO may be detrimental. Forexample, a user may be ejected from a conference call and may have toredial a bridge number, enter a password, etc. VPN traffic may besimilarly detrimentally affected by service disruption due to IP addresschange caused by SIPTO.

The WTRU may be able to identify a presence of long-lived and/orreal-time flows. For example, the WTRU may inspect the flows that havebeen established to identify which flows are relatively short livedflows and which a relatively long lived flows. The WTRU may identify theshort lived flows as flows that will result in minimal servicedisruption for the user if SIPTO is performed for the flow. The WTRU mayidentify the long lived flows as flows that will result in a relativelylarge service disruption for the user if SIPTO is performed for theflow. The WTRU may advise the network as to whether SIPTO may beperformed (e.g., without much or any disruption), based on the presenceof long-lived and/or real-time flows, for example on a per-flow basis.

In order to avoid service disruptions for long-lived flows, the WTRU maybe configured to proactively create a new PDN connection for a longlived flow prior to breaking down the existing PDN connection for thelong lived flow. Once the new PDN connection is established, the WTRUmay remove the old PDN connection for the flow. As a result of creatingthe new PDN connection prior to breaking down the old PDN connection,the WTRU may ensure that the service disruption due the SIPTO/PDN GWchange is minimized for long lived and/or real-time flows. For non-longlived flows and/or non-real-time flows (e.g., short lived flows such asthose associated with internet browsing, a chat sessions, etc.), theWTRU may indicate to the network that SIPTO/PDN GW change can beperformed without setting up the new connection prior to moving the oldconnection. The WTRU may support one or more flows via a first IPaddress with a first PDN connection. For supporting applications, theWTRU may proactively move one or more long-lived and/or real-time flowsfrom the first IP address (e.g., an existing IP address) to a second IPaddress (e.g., a new IP address). The second IP address may include anew PDN connection. The WTRU may move the one or more long-lived and/orreal-time flows to the second IP address via a second PDN connectionbefore the first IP address (e.g., first PDN connection) is removed. Forexample, a multimedia telephony service (MMTel) set of applicationsand/or other applications may be capable of proactively moving one ormore long-lived and/or real-time flows as described herein. An IMSapplication may allow a change of media transport addresses for anongoing session using IMS service continuity mechanisms.

A network may consider an end-user's expectation regarding local P-GWchange in case of SIPTO use. For example, the network may consider theend-user's expectation based on one or more end-user preferences, tobenefit from the WTRU's knowledge of the flow type of an established IPflow, and/or the like.

A WTRU may send one or more preferences to the network. The WTRU maysend the one or more preferences to the network to ensure that aseamless handover takes place when moving flows from non-SIPTO to SIPTOPDN connections and vice versa. Various network nodes, such as HSS(e.g., including subscription parameters), MME, and/or WTRU may takeactions to ensure the seamless handover. As an example, the preferenceinformation may indicate whether for a given flow a new PDN connectionassociated with a new P-GW is to be established prior to deactivatingthe an old PDN connection associated with a previous P-GW whenperforming SIPTO for the flow (e.g., for a long-lived and/or real-timeflow). The preference information for another flow may indicate that theflow can be moved to a new PDN connection associated with a new P-GWwithout having to set up the new PDN connection in advance (e.g., forshort-lived and/or non-real-time/best effort flows). Thus, amake-before-break scheme for the PDN connection may be used forperforming SIPTO for long-lived and/or real-time flows, and short livedand/or non-real-time flows may be associated with a SIPTO scheme wherethe old PDN connection is deactivated at substantially the same time asthe new PDN connection is activated (e.g., a break while make or breakbefore make scheme).

There may be a conflict between a network wanting to offload certainflows or PDN connections to SIPTO@LN and a WTRU wanting to keep anoriginal PDN connection, for example, for service continuity or otherreasons. The network and/or WTRU may handle or resolve the conflict.

A 3GPP network may use one or more subscription parameters (e.g.,subscription information) to determine whether a WTRU supportsWTRU-assisted SIPTO and/or coordinated change of P-GW. The one or moresubscription parameters may be used because one or more WTRUs in asystem may not support WTRU-assisted SIPTO and/or coordinated change ofP-GW. The one or more subscription parameters may be used because one ormore WTRUs in the system may not subscribe to WTRU-assisted SIPTO and/orcoordinated change of P-GW when signing up with an operator. The one ormore subscription parameters may specify whether the user's or WTRU'sinput is used to decide whether the traffic is subject to offloadingbetween 3GPP and non-3GPP access.

The subscription information may specify what type of traffic may besubject to offloading. For example, traffic with a specific quality ofservice (QoS) or QoS class identifier (QCI), application type, APN,subscriber profile ID (SPID), and/or the like may be subject tooffloading. As another example, all traffic except voice traffic may besubject to offloading. As another example, voice calls except foremergency voice calls may be subject to offloading. The subscriptioninformation may specify which bearers, IP flows, and/or PDN may besubject to offloading. The subscription information may specify thatbackground traffic may be subject to offloading. The subscriptioninformation may specify that a default bearer (e.g., only the defaultbearer) is subject to offloading. The subscription information mayspecify that one or more dedicated bearers (e.g., only the dedicatedbearers) are subject to offloading.

The subscription information may specify whether the network mayconsider (e.g., may always have to take into consideration) anindication and/or an assistance information sent by the WTRU for acoordinated P-GW change. The subscription information may specifywhether offloading may be applicable to a particular cell, e.g., a CSGcell, or a local network with a specific local network identity, or atracking area, etc. The subscription information may specify a list ofapplications and/or application IDs. The list of applications and/orapplication IDs may include applications that may benefit from aseamless transition to a local network and/or applications that may useinput from a user or WTRU or a preference about whether the bearercontaining such application data may be moved to SIPTO@LN.

Upon registration to the network, a HSS may provide subscriptioninformation to a MME and/or a node that is fetching the WTRU'ssubscription information (e.g., SGSN, MSC, etc.). The MME (e.g., or anode with similar functionality, such as the SGSN) may send thesubscription information to one or more core network nodes, such as theServing Gateway (S-GW) and/or the Packet Data Network (PDN) Gateway (PDNGW or P-GW).

The subscription information may be forwarded from a first MME to asecond MME during an inter-MME handover. The source may include thesubscription information as part of the transferred WTRU context. Thesource MME/SGSN may include the subscription information when handingover to another system node such as an SGSN/MME, respectively.

The subscription information may be provided to the WTRU, for example,via OMA DM, ANDSF, SMS, etc. The WTRU may provide the subscriptioninformation to the eNB. The eNB may use the subscription information todetermine whether to offload traffic. The eNB may determine whether tooffload traffic based on the subscription information and/or a WTRUpreference.

A WTRU may provide capability information to a network and/or a MME. TheWTRU may provide the capability information to the network and/or theMME via a capability information element (IE). The capability IE mayinform the MME that the WTRU may be able to send or capable of sendingone or more flow preferences to decide which flows, bearers, and/or PDNconnections may be offloaded to SIPTO@LN. The MME may use the capabilityinformation received from a HSS and/or the capability IE to determinewhether to perform network imitated SIPTO and/or WTRU-assisted SIPTOoffload.

When a WTRU enters a local network or a cell or in coverage of an eNB ora HeNB where SIPTO offload may be possible, the WTRU may be aware thatthe local network, the cell, and/or the eNB supports SIPTO offload. TheWTRU may determine whether to send one or more preferences to the localnetwork, the cell, and/or the eNB. The one or more preferences mayinclude one or more SIPTO preferences. The WTRU may send the one or morepreferences via an indication. The one or more preferences and/or theindication that may be sent to the network are disclosed herein. The oneor more preferences may be sent to the MME via a NAS message (e.g., aNAS message that may be defined for the purpose of sending one or moreSIPTO preferences to the MME).

The WTRU may be aware of whether an eNB or a cell supports SIPTO or isconnected to an L-GW. When the WTRU determines that the eNB or the cellsupports SIPTO or determines that the eNB or the cell is connected to aL-GW, the network or the MME may send a message to the WTRU. The messagemay indicate that one or more flows of the WTRU's traffic may be subjectto SIPTO@LN and/or SIPTO offloading. The WTRU may send one or morepreferences (e.g., SIPTO preferences) about one or more flows and/or anapplication that it wants to be offloaded to the SIPTO@LN PDNconnection.

The WTRU may send preference information to the MME (e.g., forcoordinated P-GW change for SIPTO). The preference information mayinclude an indication that at least one flow is available for SIPTO. Thepreference information may include one or more of the following. TheWTRU may send a tag or an IE that indicates whether SIPTO is allowed ordisallowed on one or more PDN connections (e.g., that the WTRU may haveat a given time when it moves to the local network). For example, if theWTRU has two PDN connections (e.g., a first PDN connection and a secondPDN connection) and the WTRU only wants one of the two PDN connectionsto be offloaded, the WTRU may tag one of the two PDN connections asSIPTO allowed and may tag the other PDN connection as SIPTO not allowed.The WTRU may indicate that the at least one flow available for SIPTO ison the first PDN connection. The tag may be sent via a NAS message tothe MME. The NAS message may be sent to the MME that corresponds to anIP address and/or an identity of one or more PDN connections that theWTRU may have at a given time.

The WTRU may send preference information at a finer granularity than aflow. For example, the preference information may be sent at the bearerlevel, at the IP flow level, and/or at the application level. When thepreference information is sent at the bearer level, the WTRU may specifya bearer that can be offloaded to the local network. When the preferenceinformation is sent at the IP flow level, the WTRU may specify an IPflow or flows that can be offloaded to the local network. When thepreference information is sent at the application level, the WTRU maysend one or more application IDs to the MME with a corresponding SIPTOstatus (e.g., SIPTO allowed or SIPTO disallowed) for each applicationrunning on the WTRU.

The MME may send an indication that a PDN connection is subjectoffloading. When the MME indicates that the PDN connection is subject tooffloading, the WTRU may send (e.g., respond with) an indication that itdoes not want to offload and/or may inform the network when it is readyto offload. For example, the WTRU may send the indication that it doesnot want to offload, when a WTRU has ongoing traffic that it does notwant to disrupt, such as a voice call or a video chat. When the ongoingdata session is finished, the WTRU may send an indication that it isready for SIPTO offload and/or that the network can proceed with SIPTO.

A WTRU may reject a network request for SIPTO. The WTRU may reject thenetwork request for SIPTO, when a user or the WTRU knows that the SIPTOoffload may affect a quality of service and/or a quality of experiencefor the user.

When the WTRU is in the local network and/or under the coverage of aneNB that supports SIPTO, the WTRU may send an indication to start theSIPTO offload at a next time when the WTRU goes from connected to idle.When the network receives the indication, the network may offload one ormore flows to SIPTO@LN when the WTRU moves to idle mode.

The WTRU may send the indication to the network that it may start theSIPTO offload based on one or more of the following triggers. Forexample, the WTRU may send the indication when the WTRU closes a certainapplication. The WTRU may not want to perform SIPTO when a certainapplication is running on the WTRU. The WTRU may send the indication(e.g., a start SIPTO indication) when the certain application is closeddown. When an application is started and the WTRU is in an area whereSIPTO is supported, the WTRU may send an indication to the network tostart SIPTO offload. The WTRU may also send the indication to startSIPTO offload when a display screen of the WTRU (e.g., smartphonescreen) goes to rest (e.g., when the WTRU locks or the screen goes blankbecause of inactivity). There may be an interaction between theoperating system of the phone and the 3GPP protocol stack such that whenthe screen goes blank, the 3GPP protocol stack may be notified, which inturn may send the indication to the MME, via a NAS message, that one ormore flows are ready for SIPTO offload.

When the WTRU sends preference information for the coordinated P-GWchange for SIPTO to the network (e.g., MME), the MME may determine tooffload some or all of its traffic to the local network via SIPTOoffload based on the preference information. The MME may take one ormore actions to ensure a seamless SIPTO handover. For example, the MMEmay decide not to offload traffic to SIPTO based on the WTRU preferenceinformation. The WTRU may retain an existing (e.g., the original) PDNconnection and/or bearer through the macro network PDN-GW.

When a MME receives an application ID, a flow identification, and/orother information about a flow be capable of SIPTO offloading, the MMEmay determine to offload the SIPTO capable flow based on the WTRUpreference information. For example, one or more SIPTO capable flows maybe on one or more PDN connections and/or one or more bearers. The MMEmay move the one or more flows between one or more PDN connections. TheMME may move the one or more flows, by establishing a SIPTO@LN PDNconnection or sending a message asking the WTRU to establish (e.g.,initiate) a SIPTO@LN PDN connection for a flow (e.g., every flow) movedto a local PDN-GW. For example, if the MME wants to move two flows fromdifferent macro PDN connections, the MME may request that the WTRUestablish two SIPTO@LN PDN connections. The MME may request that theWTRU and move the two flows (e.g., SIPTO capable flows) to the two PDNconnections (e.g., if different flows belong to PDN connections fordifferent APNs). The MME may request the WTRU to establish only oneSIPTO@LN and move the SIPTO capable flows to that local network PDNconnection (e.g., if the flows from different PDN connections belong tothe same APN or in some other scenarios). The MME may send or installone or more traffic filters to change the direction of one or more flowsfrom a macro network PDN connection to a SIPTO@LN. The one or moretraffic filters may include one or more Traffic Flow Templates (TFTs)and/or one or more Packet Filters (PF). The one or more traffic filtersmay direct the SIPTO capable traffic from the WTRU to the L-GW in thelocal network.

The WTRU may send a list of applications to the MME while it is attachedto the system. When the MME is about to perform SIPTO, The MME mayconfirm with the WTRU whether the WTRU is running the same applicationsin the list of applications. The MME may send a NAS message to the WTRUto check what applications are running. The MME may determine whichbearers to offload and/or whether to perform the SIPTO offload based onthe applications running on the WTRU.

When the WTRU moves into a local network, the MME may know that aSIPTO@LN offload may not be possible because when the WTRU moved intothe local network, the MME may have performed a S-GW relocation withoutmobility to the S-GW in the local network. The S-GW in the local networkmay be collocated with L-GW. One or more of the WTRU's PDN connectionsand/or EPS bearers may go through the S-GW in the local network. The oneor more PDN connections and/or EPS bearers may go through the S-GW inthe local network to prepare for when the WTRU is ready to perform SIPTOoffload as the SIPTO PDN connection may go through the S-GW in the localnetwork.

A WTRU may proactively move one or more flows (e.g., long-lived and/orreal-time flows) from a first IP address to a second IP address (e.g.,on a new PDN connection) before the first IP address (e.g., old PDNconnection) may be removed. For example, a WTRU with an IMS session maycontinue to receive or transmit voice or video media with the first IPaddress while it is setting up a second IP address via a second PDNconnection and/or performing SIP re-invitation to the second IP address.The WTRU may (e.g., simultaneously) have multiple PDN connections of thesame APN, but to different PGWs (e.g., to continue to receive ortransmit voice or video media with the first IP address while setting upthe second IP address).

FIG. 2 illustrates an example call flow 200 for a SIP session withre-invite. A first WTRU 202 may establish a connection with (e.g.,invite) a second WTRU 206. The connection may be established through aproxy 204. At some point during the connection, the second WTRU 206 maychange an IP address 208. The change in IP address 208 interrupts (e.g.,breaks) the connection between the first WTRU 202 and the second WTRU206. The second WTRU 206 must re-establish the connection with (e.g.,re-invite) the first WTRU 202.

A WTRU may be triggered to establish (e.g., create) a PDN connection forSIPTO via a NAS message. The NAS message may include a PDN deactivationmessage with ESM cause “reactivation requested.” Establishing a PDNconnection in response to a PDN deactivation message may be described asbreak-before-make in nature. A trigger (e.g., from the network) may beused to inform the WTRU to perform a PDN connectivity request withoutdeactivating the existing PDN connection. For example, a message may besent from the MME to the WTRU for establishing a PDN connection of agiven APN. The message may be sent via a NAS ESM message. The WTRU maysend an indication, to the MME, that at least one flow of a first PDNconnection is available for SIPTO. The MME may send the message afterreceiving the indication from the WTRU that the at least one flow of thefirst PDN connection is available for SIPTO and the network decides toperform SIPTO. The message may be triggered by WTRU mobility. Forexample, the message may be sent when the WTRU moves out of a first LHNarea to a second LHN area.

When the WTRU has moved the traffic from a first PDN connection to asecond PDN connection, if the WTRU has not received any packets from thefirst PDN connection for a period of time, it may request thedeactivation of the first PDN connection.

FIGS. 3 and 4 illustrate an example network 300 employing amake-before-break SIPTO PDN connection. As shown in FIG. 3, a WTRU 304may have a first PDN connection 312 (e.g., an existing PDN connection)with a first P-GW 306. The first PDN connection 312 may be via a firstL-GW or a first eNodeB 318 and a S-GW 310. One or more flows may be sentvia the first PDN connection 312. An MME 302 may send a message 314 tothe WTRU 304. The message 314 may trigger the WTRU to establish (e.g.,to create) a second PDN connection 316 (e.g., a new PDN connection) witha second P-GW 308. The WTRU 304 may establish the second PDN connection316. The WTRU 304 may establish the second PDN connection 316 withoutdeactivating the first PDN connection 312. The MME 302 may send themessage 314 to the WTRU 304 based on a trigger condition disclosedherein, a load condition of the first P-GW 306 of the first PDNconnection 312, and/or by a location (e.g., an anticipated location) ofthe WTRU 304 where a second P-GW 308 may be closer to the WTRU's pointof attachment. The WTRU 304 may perform a PDN connectivity request. TheMME 302 may provide the IP address of the second P-GW 308 to the S-GW310. The WTRU 304 may move one or more flows from the first PDNconnection 312 to the second PDN connection 316. The WTRU 304 may stoptransmitting on the first PDN connection 312.

As shown in FIG. 4, the WTRU 304 may deactivate the first PDN connection312 when it has completed moving one or more flows (e.g., all theexisting flows) to the second PDN connection 316 and/or when noinformation (e.g., data) has been received via the first PDN connection312 after a predetermined duration.

While FIGS. 3 and 4 illustrate the WTRU 304 moving from the first L-GWor first eNodeB 318 to a second L-GW or second eNodeB 320, the disclosedsubject matter may also be applicable when the WTRU 304 remainsconnected to the first eNodeB 318 or cell.

FIGS. 5 and 6 illustrate an example network 500 employingmake-before-break SIPTO for the case of SIPTO@LN with a standalone L-GW.The standalone L-GW may be a first L-GW 514. SIPTO@LN may assume that atarget S-GW selected during the handover may have connectivity to thefirst L-GW 514. SIPTO may use the connectivity to the first L-GW 514 fordeactivation after a mobility event or a possible S-GW relocation. Giventhis assumption, deactivation of a first PDN connection 518 may bedeferred until sometime after handover to a different LHN area or amacro cell.

A make-before-break SIPTO procedure in the case of SIPTO@LN may includean MME 502 sending a message 522 to a WTRU 504. The message 522 maytrigger the WTRU 504 to establish (e.g., to create) a second PDNconnection 520 with a second P-GW 506. The WTRU 504 may establish thesecond PDN connection 520 without deactivating the first PDN connection518. For example, the message 522 may be sent by the MME 502 when theWTRU 504 moves to a different LHN area, or to a different macro cell.The WTRU 504 may perform a PDN connectivity request. The MME 502 mayprovide the IP address of the second P-GW 506 to a second S-GW 508. TheWTRU 504 may move one or more flows from the first PDN connection 518 tothe second PDN connection 520. The WTRU 504 may stop transmitting on thefirst PDN connection 518.

As shown in FIG. 6, the WTRU 504 may deactivate the first PDN connection518 when it has completed moving one or more flows (e.g., all theexisting flows) to the second PDN connection 520 and/or when noinformation (e.g., data) has been received via the first PDN connection518 after a predetermined duration. The MME 502 may perform anMME-initiated S-GW relocation from a first S-GW 510 to a second S-GW508, if the S-GW has not been relocated to the S-GW 508 during themobility procedure.

The MME 502 may send the message 522 to the WTRU 504 and the WTRU 504PDN connectivity request may be performed before the WTRU 504 moves outof a first LHN area (e.g., served by L-GW 514). For example, the MME 502may send the message 522 if the MME 502 knows a LHN-ID for a second LHNarea of which the WTRU 504 has not yet moved into. The second LH areamay be associated with the second PDN connection 520. The LHN-ID may beprovided by a source eNB to the MME 502. The MME may send the LHN-ID ofthe second PDN connection 520 to the WTRU 504. The LHN-ID may include anIP address of a P-GW associated with the second PDN connection 520.

FIGS. 7 and 8 illustrate an example network 700 employingmake-before-break SIPTO for the case of SIPTO@LN with a first L-GW 714collocated with a first P-GW 710. SIPTO@LN may assume that a target S-GW708 selected during the handover may have connectivity to the first L-GW714. SIPTO may use the connectivity to the first L-GW 714 fordeactivation after a mobility event or possible S-GW relocation. Giventhis assumption, deactivation of a first PDN connection 712 may bedeferred until sometime after handover to a different HeNB or a macrocell.

A make-before-break SIPTO in the case of SIPTO@LN may include an MME 702sending a message 720 to a WTRU 704. The message 720 may trigger theWTRU 704 to establish (e.g., to create) a second PDN connection 718 witha second P-GW 706. The WTRU 704 may establish the second PDN connection718 without deactivating the first PDN connection 712. For example, themessage 720 may be sent by the MME 702 when the WTRU 704 moves to adifferent HeNB or macro cell. The WTRU 704 may perform a PDNconnectivity request. The MME 702 may provide the IP address of thesecond P-GW 706 to the S-GW 708. The WTRU 704 may move one or more flowsfrom the first PDN connection 712 to the second PDN connection 718. TheWTRU 704 may stop transmitting on the first PDN connection 712.

As shown in FIG. 8, The WTRU 704 may deactivate the first PDN connection712 when the WTRU 704 has completed moving one or more flows (e.g., allthe existing flows) to the second PDN connection 718 and/or when noinformation (e.g., data) has been received via the first PDN connection712 after a predetermined duration.

A SIPTO bearer context may be transferred between MMEs when the WTRUperforms TAU from idle mode. Transfer of the SIPTO bearer context may beperformed via an indication that may identify the SIPTO bearer. Theindication may be used by a target LGW to perform APN-AMBR policing, asdescribed herein.

In an example EPS architecture, for the same APN there may be a P-GW(e.g., only one P-GW). The P-GW may enforce APN-AMBR. An APN may havetwo P-GWs, which may make APN-AMBR policing difficult.

For SIPTO above RAN, the S-GW 708 may perform APN-AMBR monitoring. TheS-GW 708 may know the APN-AMBR and information relating to which beareror bearers belong to the APN.

For SIPTO@LN, APN-AMBR monitoring may be located at a LGW (e.g., eithercollocated with SGW or eNB). The LGW may already perform APN-AMBRmonitoring of a first PDN connection 712. A first APN-AMBR of the firstPDN connection 712 may be summed with a secondAPN-AMBR of a second(e.g., a new) PDN connection 718. The LGW may meter the second PDNconnection 718. The sum of the first APN-AMBR and the second APN-AMBRmay be policed.

For a collocated LGW with an eNB, the eNB may not know which bearerbelongs to the first SIPTO PDN connection 712. The MME 702 may signalthis bearer identity to a target eNB.

The MME 702 may separate the APN-AMBR into components that may bedesignated, for example, as a first APN-AMBR and a second APN-AMBR. Forexample, APN-AMBR=the first APN-AMBR+the second APN-AMBR. The MME 702may receive subscription data. The subscription data may include theAPN-AMBR. The MME 702 may determine a modified first APN-AMBR. The MME702 may modify the APN-AMBR to the first APN-AMBR for the first PDNconnection 712 (e.g., before the WTRU 704 performs a PDN connectivityrequest). The MME 702 may signal the modified first APN-AMBR to aneNodeB. The MME 702 may send a modified bearer command to a s S-GW 708.The modified bearer command may identify the modified first APN-AMBR.The MME 702 may modify the second APN-AMBR-to APN-AMBR for the secondPDN connection 718 (e.g., after the WTRU 704 deactivates the second PDNconnection 718).

The processes and instrumentalities described herein may apply in anycombination, may apply to other wireless technology, and for otherservices.

A WTRU may refer to an identity of the physical device, or to the user'sidentity such as subscription related identities, e.g., MSISDN, SIP URI,etc. WTRU may refer to application-based identities, e.g., user namesthat may be used per application.

The processes described above may be implemented in a computer program,software, and/or firmware incorporated in a computer-readable medium forexecution by a computer and/or processor. Examples of computer-readablemedia include, but are not limited to, electronic signals (transmittedover wired and/or wireless connections) and/or computer-readable storagemedia. Examples of computer-readable storage media include, but are notlimited to, a read only memory (ROM), a random access memory (RAM), aregister, cache memory, semiconductor memory devices, magnetic mediasuch as, but not limited to, internal hard disks and removable disks,magneto-optical media, and/or optical media such as CD-ROM disks, and/ordigital versatile disks (DVDs). A processor in association with softwaremay be used to implement a radio frequency transceiver for use in aWTRU, UE, terminal, base station, RNC, and/or any host computer.

1-16. (canceled)
 17. A method implemented by a wireless transmit/receiveunit (WTRU), the method comprising: determining, by the WTRU, preferenceinformation associated with an application of the WTRU; sending, by theWTRU, a first message including the determined preference informationthat indicates, for a flow associated with the application, that adeactivation of a first session associated with a first anchor point isafter an establishment of a second session associated with a secondanchor point; communicating, by the WTRU, data associated with the flowvia the first anchor point using the first session associated with afirst IP address; receiving, by the WTRU, a second message triggeringthe establishment of the second session and a movement of the flow tothe second session; establishing, by the WTRU, the second sessionassociated with the second anchor point; moving, by the WTRU, the flowfrom the first session that is associated with the first IP address tothe second session that is with a second IP address; and after themoving of the flow to the second session, communicating, by the WTRU,data associated with the flow via the second anchor point using thesecond session associated with the second IP address.
 18. The method ofclaim 17, wherein the first anchor point corresponds to a first gatewayand the second anchor point corresponds to a second, different gateway.19. The method of claim 17, further comprising, after the moving of theflow to the second session, deactivating the first session.
 20. Themethod of claim 17, wherein the first session is associated with a firstpacket data network (PDN) connection and the second session isassociated with a second PDN connection.
 21. The method of claim 17,wherein the first session corresponds to an IP multimedia subsystem(IMS) session.
 22. The method of claim 17, further comprising:receiving, by the WTRU, information indicating one or more policiesassociated with the application of the WTRU; and determining, based onthe one or more indicated policies, whether to seamlessly move the firstflow to the second session prior to the deactivation of the firstsession.
 23. The method of claim 17, wherein the first message is anon-access stratum message and the preference information is aninformation element (IE) of the non-access stratum (NAS) message.
 24. Awireless transmit/receive unit (WTRU), comprising: a processorconfigured to determine preference information associated with anapplication of the WTRU; and a transmitter/receiver configured to: senda first message including the determined preference information thatindicates, for a flow associated with the application, that adeactivation of a first session associated with a first anchor point isafter an establishment of a second session associated with a secondanchor point, communicate data associated with the flow via the firstanchor point using the first session associated with a first IP address,and receive a second message to trigger the establishment of the secondsession and a movement of the flow to the second session, wherein: theprocessor is configured to: establish the second session associated withthe second anchor point, move the flow from the first session associatedwith the first IP address to the second session associated with thesecond IP address, and the transmitter/receiver configured to: after themovement of the flow to the second session, communicate data associatedwith the flow via the second anchor point using the second sessionassociated with the second IP address.
 25. The WTRU of claim 23, whereinthe first anchor point corresponds to a first gateway and the secondanchor point corresponds to a second, different gateway.
 26. The WTRU ofclaim 23, further comprising, after the movement of the flow to thesecond session, deactivating the first session.
 27. The WTRU of claim23, wherein the first session is associated with a first packet datanetwork (PDN) connection and the second session is associated with asecond PDN connection.
 28. The WTRU of claim 23, wherein the firstsession corresponds to an IP multimedia subsystem (IMS) session.
 29. TheWTRU of claim 23, wherein the first message is a non-access stratum(NAS) message and the preference information is an information element(IE) of the non-access stratum (NAS) message.
 30. The WTRU of claim 23,wherein: the transmitter/receiver is configured to receive informationindicating one or more policies associated with the application of theWTRU; and the processor is configured to determine, based on the one ormore indicated policies, whether to seamlessly move the first flow tothe second session prior to the deactivation of the first session.